A year after being elected to his first public office after five previous tries, state Sen. Jim Oberweis on Friday formally announced his bid for the Republican U.S. Senate nomination.

Oberweis, a Sugar Grove money manager and boutique dairy owner, used a five-minute web video to make the announcement. At times, he sounded defensive in acknowledging both his political critics and past mistakes as a candidate.

Oberweis’ decision to try to challenge Democratic U.S. Sen. Dick Durbin’s bid for a fourth term had been expected. But many top Republicans — including the GOP leaders of the state legislature — have contended controversies surrounding Oberweis’ previous campaigns could hobble the Republican ticket and urged him not to run.

Those controversies included a statement about abortion and religious intolerance as well as a TV ad in which he flew in a helicopter over Soldier Field and contended that enough “illegal aliens” cross the U.S. border to fill the stadium every week. His figures were strongly criticized as exaggerations.

“Some people are going to want to talk about my mistakes as a candidate over the last 10 years. I have made mistakes. I’ve made statements and commercials that I regretted, and I’ve said so,” Oberweis said in the video.

The freshman state senator also touted his ability to work with Democrats to get one of the two bills he sponsored signed into law — a measure raising interstate highway speed limits. Oberweis said he considered state Sen. Martin Sandoval, a Chicago Democrat who chairs the Illinois Senate Transportation Committee, “a friend.”

“Before being elected, do you think my detractors would have predicted my first bill in the Illinois legislature would pass through a Democrat-controlled Senate and House and then be signed by a Democrat governor? I can tell you, the answer is no,” he said.

Oberweis previously ran statewide and lost twice for the Republican U.S. Senate nomination and once for the GOP governor nomination. He also special and general election contests for Congress.Oberweis said “politicians are more concerned with their next election, instead of what is best for America” and vowed to serve only two terms as he labeled Durbin, the No. 2 ranking Democrat in the Senate, a “Washington insider.”

In addition to Oberweis, political newcomer and suburban businessman Doug Truax of Downers Grove also is expected to seek the Republican nomination. Candidate filing starts Monday and runs through Dec. 2.